This invention relates to fabric softener compositions comprising certain red colorants that exhibit excellent deep, dark red colorations (for aesthetic purposes) and mix very well with other colorants to provide differing red shades and tints therein, which simultaneously exhibit very low, if any staining capabilities on fabrics treated therewith. Such deep and dark red colorations have heretofore been unavailable within fabric softener formulations due to the tendency of such prior colorants to exhibit unacceptable staining levels, particularly when formulated at similar deep and dark shades as now provided within the inventive low-staining formulations. Apparently, and quite unexpectedly, the colorants present therein interact favorably with quaternary ammonium salt softening agents in a manner to prevent reaction with the fibers of the treated fabrics themselves, thereby preventing staining thereon and therein. Such novel red-colored or -tinted fabric softener formulations, as well as any other quaternary-ammonium salt-containing red-colored or -tinted compositions are encompassed within this invention.
All U.S. and foreign patents cited within this specification are hereby incorporated by reference.
Fabric softeners have been provided as colored formulations for aesthetic reasons and brand identity. Although white and/or clear compositions have been commercialized in the past as well, the modern consumer often prefers attractively colored cleaning, etc., products.
Fabric softener compositions are known in the art and are used in rinse cycles of automatic laundry operations to impart improved hand and anti-static properties to laundered fabrics. The first U.S. concentrated (6-10% active) rinse cycle fabric softener was introduced in the 1960s. These were added during the final rinse of the wash cycle and were usually quaternary types, mainly di(hydrogenated) tallow dimethylammonium chloride (DHTDMAC), although some were based on imidazoline or amido amine derivatives. The products were essentially aqueous solutions or suspensions containing 4-6% active softener, a fabric substantive fragrance and a viscosity modifier.
In 1990, ultra formulations, (17-28% solids), e.g., xe2x80x9ctriple concentrates,xe2x80x9d were introduced in the U.S. and are increasing in the marketplace owing to their reduced packaging and transportation costs. Such formulations require particular care in ingredient formulation, mixing, viscosity control, and final formulation viscosity stability in order to provide stable, low viscosity products. See, e.g., xe2x80x9cFormulation and Production of Concentrated Rinse Cycle Fabric Softeners,xe2x80x9d Robert O. Keys, happi/March 1995, pp. 95-97, and xe2x80x9cFabric Conditioning Agents,xe2x80x9d George R. Whalley, happi/February 1995, pp. 55-58. Recently, formulations have reduced or replaced DHTDMAC, e.g., by ester quats or ester amines, in order to facilitate product breakdown in the ecosystem, particularly in Europe. These formulations also require special considerations to provide a commercial product of the proper viscosity.
Colorants are generally added to liquid fabric softening compositions for visual appeal to the consumer as well as identity of the product. Fabric staining caused by softener compositions can be permanent; however, initial staining may not always be obvious to the consumer due to potentially and relatively low levels of discoloration during individual laundry cycles. Thus, staining may actually accumulate on target fabrics over a period of time rather than during a single wash.
Colorants employed in fabric softener compositions are preferably those which are easily removed from fabric if color staining, or possibly staining due to softener compounds themselves, occurs. Such colorants thus must exhibit a very low and reduced tendency to stain commonplace fabrics such as cotton and polyester. Dyes of high color stability in the fabric softener compositions which exhibit minimal complexation or reaction with other fabric softener ingredients and the laundered fabrics themselves are of particular interest in fabric softener composition applications. Among these dyes are certain polymer-bound colorants which are available from Milliken Chemical Co. as Liquitint(copyright) colorants whose incorporation in liquid fabric softening compositions is noted in published international application WO 94/10285 as well as direct dyes, acid dyes, F,D and C Dyes (e.g., Red 40), rhodamines, pigments, and the like, which impart red colorations to liquid softener formulations, but also have a tendency to stain targeted fabrics, particularly when present at levels that provide deep and dark red shades. To date, red colorants providing deep and dark red shades, specifically at high L, c, and h values as noted below, within fabric softening compositions have been unavailable to the industry without also exhibiting unacceptable staining levels.
As alluded to above, it is desirable, to provide aesthetically pleasing red colorations for liquid fabric softener compositions, wherein the colorants are stable in low pH (e.g., from about 1 to 4) cationic compound-containing liquid formulations, non-staining, and capable of high color loading and bright coloration without precipitating out of the composition. In particular, colorants are desired which provide an increase in the ease of stain removal versus the aforementioned commonly used red colorants and dyes within liquid fabric softener compositions. The red colorants traditionally introduced within liquid fabric softener formulations simply cannot provide the low staining properties with simultaneously the aforementioned aesthetically desirable deep and dark red shades or, alternatively, the ability to thoroughly mix with other colorants to provide pink or reddish shades or tints within the target liquid composition. Such traditional colorants (e.g., acid dyes, pigments, etc.) unfortunately were difficult to incorporate within the low-pH cationic formulations common with liquid fabric softeners. Apparently, such colorants cannot achieve the desired color space characteristics without also exhibiting unacceptably high stain levels on certain fabric substrates. As such, there remains a need to provide such aesthetically useful, non-staining colorations within liquid fabric softeners.
It is thus an object of the invention to provide a liquid fabric softener composition which is brightly colored through the utilization of at least one water-soluble non-staining red colorant. It is another object of this invention to provide a red colorant that mixes thoroughly with other colorants within liquid fabric softener formulations to permit production of different brightly colored shades of pink, orange, violet, or, of course, red therein, while simultaneously exhibiting essentially no staining of target fabrics contacted therewith during an aqueous rinse of a standard laundry procedure (e.g., either by hand or within a tumble, rotary, or other type of washing machine). A further object of the invention is to provide a liquid fabric softener formulation that will not exhibit any appreciable staining on target substrates and thus only provides red colorations within and to the target liquid fabric softener composition. Yet another object of this invention is to provide a red colorant that provides color in the presence of cationic softener compounds but will not appreciably react with fiber constituents of target fabrics. Accordingly, this invention is directed to a fabric softener composition comprising at least one fabric softening component and at least one red colorant that provides excellent high color space characteristics and exhibits a simultaneously low tendency to stain target fabrics, as well as the use of such compositions for conditioning fabrics in an aqueous wash. More particularly, this invention relates to a liquid fabric softener composition comprising a hemicyanine colorant, preferably having an electrophilic reactive group reacted with a poly(oxyallylene)-containing moiety having a nucleophilic reactive group to provide a polymeric colorant.
The present invention thus encompasses a liquid fabric softener composition comprising at least one cationic fabric softener compound and at least one water-soluble red hemicyanine derivative colorant, preferably a polymeric derivative of such a colorant, either as the sole colorant to provide a red hue, or as a component within a mixture of colorants to provide any number of different hues. Alternatively, this invention encompasses a liquid fabric softener composition comprising at least one cationic fabric softener compound and at least one red colorant, wherein said liquid fabric softener composition exhibits a red color characterized by a color space in terms of CIELAB values under D65 illumination of an L* value of at least 30, an a* value of at least 20, a b* value of between xe2x88x9220 and 20, a C* value of at least 20, and an hxc2x0 of between 0 and 30xc2x0 and 300xc2x0 and 360xc2x0, wherein said red-colored liquid fabric softener exhibits a stain level of at least 4 upon contact with a 100% terry cotton fabric substrate pursuant to the AATCC Gray Scale For Evaluating Staining. Furthermore, this invention encompasses a red colorant that exhibits a color space in terms of CIELAB values under D65 illumination of an L* value of at least 30, an a* value of at least 20, a b* value of between xe2x88x9220 and 20, a C* value of at least 20, and an hxc2x0 of between 0 and 30xc2x0 and 300xc2x0 and 360xc2x0, and exhibits a stain level of at least 4 upon contact with a 100% terry cotton fabric substrate pursuant to the AATCC Gray Scale For Evaluating Staining when present within a liquid composition comprising at least 3% by weight of a specific quaternary ammonium cationic fabric softener compound (either Accosoft(copyright) 501 or 808, as listed below). Lastly, this invention encompasses a method of treating fabrics within a rinse cycle of a standard laundering method within a rotary washing machine comprising the steps of a) providing a liquid fabric softener composition as discussed above; b) providing at least one target fabric substrate within said rotary washing machine; and c) introducing, at a point in time after said at least one target fabric substrate has been subjected to a cleaning stage within a standard laundering process within said rotary washing machine, preferably during the rinse cycle of said process, said liquid fabric softener in an amount sufficient to impart softening characteristics to said target fabric.
The inventive colorants have unexpectedly been found to function very well in solution with low pH, cationic fabric softener compounds. To that end, such colorants have been found to provide the above-delineated highly desirable color space characteristics to permit deep and dark red colorations within target liquid fabric softener formulations. Furthermore, such colorants, being polymeric in nature, preferably, exhibit very low, if no, staining properties of fabrics when utilized in combination with such cationic softener compounds. Thus, such fabrics as cotton, polyester, poly/cotton blends, nylon, and the like, can be treated (such as, for example, during the rinse cycle of a standard rotary laundering procedure) with liquid fabric softeners comprising such red colorants and not exhibit any appreciable staining caused thereby. Such colorants are thus very compatible with the cationic (e.g., for example, quaternary ammonium) compounds required of such fabric softener compositions, and also exhibit compatibility with standard fragrances and preservatives, as merely examples, without complexing or destabilizing the resultant mixture. The inventive colorants can withstand the presence of quaternary ammonium compounds (as well as the associated pH levels imparted thereby, particularly between 1 and 4) and thus can be utilized in any liquid media comprising quaternary ammonium compounds, primarily, as noted throughout, fabric softener compositions, but also, to a lesser but possible extent, certain cleaning solutions, antistatic sprays, and the like. Lastly, since the inventive colorants produce true solutions and not emulsions nor dispersions, the formulations made therefrom are homogeneous (not clear) and brilliant in appearance, and can easily mix with other colorants, including traditional red colorants (as well as others) to form different non-staining colorations, shades, tints, etc. (such as pink, orange, purple, and the like), within target formulations.
The inventive colorants and thus formulations made therewith also exhibit excellent light fastness, particularly over a long shelf life. The color space values will generally not become modified over time and upon exposure to standard fluorescent or incandescent lighting such that the desired colorations are retained for long periods of time.
Preferably, as noted above, the particular hemicyanine derivative colorant is polymeric in nature, and most preferably comprises poly(oxyalkylene) pendants groups thereon. Such poly(oxyalkylene) groups are selected from polyethyleneoxy (EO), polypropyleneoxy (PO), and polybutyleneoxy (BO) groups, although longer chain monomers may also be utilized (up to about 18 carbons, for example). Preferably these moieties are all EO groups, although combinations of EO and any of the others may be utilized as well. Preferably from about 2 to about 200 moles of alkyleneoxy groups are present on each separate polyoxyalkylene pendant group; more preferably from about 2 to 50 moles; and still more preferably from about 5 to 25 moles, and most preferably about 20 moles. The term xe2x80x9cpolyoxyalkylenexe2x80x9d is intended to encompass any pendant group that includes at least two alkyleneoxy moieties.
The addition of polyoxyalkylene groups to the hemicyanine base compound may be accomplished through the reaction of a poly(oxyalkenylated) aniline aldehyde with Fisher""s Base to form the needed conjugated system to produce colorations in the visible spectrum as well as the desired polymeric species. Such a reaction is described in greater detail below.
The preferred hemicyanine is most easily understood through the representation of the following formula (I) 
wherein R1 is H or C1-C20 alkyl; R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are the same or different and are selected from the group consisting of H, C1-C20 alkyl, C1-C20 alkoxy, C1-C20 hydroxyl, amino, hydroxyl, and C1-C20carboxyl; R"" is C1-C16 alkyl; a is 0-200 and b is 0-200, wherein a+bxe2x89xa73; X is H or COCH3; and any counter ion may be present, such as, without limitation, OHxe2x88x92, Clxe2x88x92, CH3COOxe2x88x92, or HSO4xe2x88x92. Preferably, through not necessarily, such a compound is present wherein R1 and R6 are methyl and the remaining R groups are hydrogen, and further wherein a is about 20, b is 0, X is COCH3, and the counter ion is OHxe2x88x92.
The only previous utilizations of hemicyanine type colorants to any great extent have been in the fields of fugitive yarn colorants, as in U.S. Pat. No. 4,877,411 to Hines et al., which permit color to be temporarily applied to target yarns for identification purposes, or film development, apparently to provide certain hues within the finished picture, such as taught within U.S. Pat No. 5,534,405 to Nishigaki et al., and U.S. Pat. No. 6,066,432 to Yanaka. No teachings have been provided of liquid formulations of such types of colorants, let alone polymeric derivatives thereof, in combination with quaternary ammonium compounds or cationic fabric softeners, within the pertinent art to provide an effectively colored liquid formulation which does not exhibit appreciable coloring or staining of target fabrics upon treatment therewith.
Preferably, the water soluble polymeric hemicyanine derivative colorants are liquid in nature at ambient temperature and pressure and at substantial purity; however, pasty or waxy colorants (which are readily soluble in water) are also encompassed within this invention and may be added to fabric softener formulations, particularly in combination with viscosity modifying agents (such as, without limitation, calcium chloride) to provide the desired viscosity level (of between about 10 to about 1,500 cps to permit sufficient pourability). The term ambient temperature and pressure means from about 20 to about 25xc2x0 C. at a pressure of from about 0.8 to about 1.2 atmospheres. Furthermore, substantial purity means that the colorant is at least 90% free from solvent, diluent, surfactant, and any other compound which may dilute the colorant compound. The target inventive compositions will include at least one cationic, preferably quaternary ammonium, fabric softener compound, as well as other standard softener additives, such as resins, preservatives, pH adjusters, foam depressants, antistatic compounds, enzymes, bactericides, fungicides, stabilizers, and the like, in addition to at least colorant as defined above. However, these additive compounds do not factor into the measure of the liquid state of the target colorants of this invention and are merely required within the inventive compositions upon production thereof.
Such inventive compositions may comprise any type of fabric softening formulations and compounds. Formulations of suitable fabric softener compositions of the present invention except the colorant are disclosed in U.S. Pat. No. 5,183,580 to Lew et al., U.S. Pat. No. 5,207,933 to Trinh et al., U.S. Pat. No. 5,204,010 to Klewsaat, U.S. Pat. No. 5,290,475 to Wixon, U.S. Pat. No. 5,130,035 to Dell""Armo et al., and U.S. Pat. No. 5,089,148 to Van Blarcom et al. The liquid fabric softener composition of the present invention would include from about 3 to about 50% by weight of the total composition, preferably from 15 to about 35% by weight of a cationic fabric-softening compound, preferably a quaternary ammonium compound. The counter ion may be a halide, such as fluoride, chloride, bromide, or iodide. Other counter ions may be employed such as methylsulfate, ethylsulfate, hydroxide, acetate, formate, sulfate, carbonate, and the like. Preferably, the counter ion is chloride or methylsulfate, chloride being especially preferred for liquid fabric conditioning compositions of the present invention. Generally, concentrated liquid fabric softener compositions of the present invention can contain 17% to 50% solids (diluted with major amounts of water, either deionized or tap in nature). Particulate fabric softening compositions of the present invention can be prepared according to the formulation set out in U.S. Pat. No. 5,332,513 to Doms et al.